As a small-town european kid not very interested in geography, this is what the US geography (biased by movies/comics) looked like in my mind:

My very first mental model of the US geography (biased by movies and comics)

New York was sitting in the center of this circle and Los Angeles was to be found somewhere along the circumference (preferably on the west side of the circle).

With time (and growing interests, travels to the US and media over-exposure) my mental model of US has grown to the point of being more accurate – or at least this is what I thought…

Sketching my own mental model of US geography

I decided to sketch the map of the US together with the cities that I believed I could roughly pinpoint on the map. This is a nice exercise to investigate how your mind distorts space and maps things into its own space (i.e mental model)

This is how the US looks like in my mind. I tried to add as many details as possible from my memory.

CAUTION! The following map was sketched from my own memory it is not accurate and, as you’ll read below, some bits of it are plain wrong!

My most accurate representation of USA

How many errors can you spot?

Actually, I cannot spot any error. This is how the map looks like in my mind: it’s my own -most accurate- depiction of US geography. So, to spot the errors I have to turn to real data.

The overall shape

Using the maps library for R, I’m comparing my own US shape with the actual US shape.

The red outline is my mental model of US shape. Green squares represent a topological match, red arrows depict the mismatch and the yellow square is used to represent a misplaced (but correct) topological feature.

Ah! The horror! In retrospect, I should have included San Francisco, Seattle and New York’s bays in my model. Those bays were definitely in my model (and they also helped me to correctly pinpoint those cities – read below)

Anyways, my overall mental model is so distorted that pinpointing cities on it would make no sense. So I tried to use the real US geography as a guide for mapping the cities.

Pinpointing cities on the real map

Again, this map is wrong! I’ve tried to map cities on it from my own memory.

I tried my best… I’m pretty confident about San Diego, San Francisco, New Orleans, Seattle and Miami. But let’s have a reality check…

Real Vs Mental-Model-derived locations of US cities: the Error Map

Green squares represent cities that were mapped in the correct location. Red arrows point from the mental to the actual location of the city.

I did a very poor job. My plan was to calculate the average error (i.e. the average displacement error between mental and actual location) but that’s way too embarrassing!

I was correct only for the cities that are close to prominent geological or geographical features (i.e. bays or borders). I’ve also assigned a couple of cities to the wrong state (Cincinnati and Newark were assigned to Kentucky and New York, respectively!)

Probably the most embarrassing error is my inability to pinpoint cities relative to each others (i.e. Does Detroit seats on the west or east of Chicago?).

These models could be viewed as shortcuts (or approximate representations of the “external reality”) that provide the knowledge necessary to successfully act on our environment. However, they can also lead to nasty bias or errors – don’t ask me how much it takes to go from Cincinnati to Las Vegas…